Jump to content

How are resin aftermarket patterns made?


Recommended Posts

Just curious about this. Many sets, for example, those in 1/72, have tiny details like the instrument gauges. I have no idea how any of this can be sculpted by hand with such tiny details like the tick marks. Can anyone give any insight?

Link to post
Share on other sites

And why do certain manufacturers sets seem to not fit the kit they were designed for? It would seem that part of the process would be attempting to fit the sets into the kit.

Link to post
Share on other sites

Some of the masters on a couple of kits I recently built looked to be 3D printed. Doesn't splain those spiffy A-6 GRU5 seats I recently got from Hypersonic, though.

 

As for fit, yeah, I've had everything from Wolfpack's drop-in cockpit, wheel wells, nozzle (and I can't remember what else) for Academy's MiG-21MF to a knock-down drag-out to get an Aires wheel well into the Tamiya Mustang III.

Link to post
Share on other sites

with regard to the fitting/non-fitting.. 

 

Some make a cockpit to the model, and some to the original... due to the thickness of the plastic with regards to the plate from the real aircraft some adaptations have to be made so that it would fit. I'd say it's some give and take to satisfy everybody, which you can't anyway...

 

With regards to the tiny details I'm curious too...

Link to post
Share on other sites

Fit of parts or no fit:

When designing my ejection seats, it was easy: I went out to my collection, took measurements of the real seat and made the master from it. It was fascinating to see that some kit manufacturers made cockpits where the resin seat either would not fit into or have tons of space around it. Fortunately for most the fit was good.

As a manufacturer it is not possible to make seats custom “distorted” to particular kit manufacturers cockpits. To make such a range would be uneconomic. I believe in making a real scale copy of the true ejection seat. There are other manufacturers with different thinking. Be it.

 

As to fine details on the masters: a steady hand, good tools, a very wide variety of materials used, including a creative use of whatever is around and the good old hand /eye coordination. It is important to have an open mind for different materials, tools and technologies which in most cases have nothing to do with model building! Incorporating them all in the model or the master can result in some great things. Just remember when in mid 1980's Tim Perry of PP Models from Bristol first introduced photoetch into our hobby developing it to a true art form!

3D printing has/could have its place in master making but it does not replace and over-rule everything else.  There are lots of bad examples where 3D print is used exclusively for master pattern making! 

Human eye and hand is still important!

 

Best regards

Gabor

Link to post
Share on other sites
12 hours ago, ya-gabor said:

Fit of parts or no fit:

 

When designing my ejection seats, it was easy: I went out to my collection, took measurements of the real seat and made the master from it. It was fascinating to see that some kit manufacturers made cockpits where the resin seat either would not fit into or have tons of space around it. Fortunately for most the fit was good.

 

As a manufacturer it is not possible to make seats custom “distorted” to particular kit manufacturers cockpits. To make such a range would be uneconomic. I believe in making a real scale copy of the true ejection seat. There are other manufacturers with different thinking. Be it.

 

Best regards

 

Gabor

To me it seams pointless wasting time on a set that may may be a exact scale down of the real thing, if it's not going to fit the kit (or any kit). 

 

As a consumer it pisses me off buying a nice aftermarket seat and finding out it doesn't fit the kit , For example, the Quickboost 1/48 Lightning seat is lovely but it's far to large to fit the Airfix kit. I'm now pretty wary on buying seats these days because the last few I've bought, (Neomega for the Kittyhawk Jag and Pavla for the Kinetic Sea Harrier) just didn't fit in the kits. 

 

That said, I do understand that for things like Ejection seats it can be hard to make a seat to fit every kit, especially if the aircraft is a popular subject (like the F-16). 

Link to post
Share on other sites

I've posted several in-progress posts you can find in the Zactomodels sub-forum above in the Sponsors section.

 

For the most part the techniques are the same as you'd find in the more elaborate builds in the in-progress sub-forum.

One big difference being that as a pattern maker you usually can't just glue the parts together as you go, they have to be separate so they can later be molded. This means making patterns is much more challenging than just scratch-building details.

 

When it comes to tiny details such as the gauges the OP mentioned, it can be just a very skilled modeler hand-making parts, 'borrowing' existing details from another kit, 3D printing or maybe using existing or custom photo-etch.

The smallest, most detailed parts I offer are my 1/144 F-15 detail parts. I didn't show an in-progress but the seat was just carefully hand-made from plastic with belts from foil. For the exhaust I hand-made one petal from plastic (very tiny!), molded and cast multiples then assembled them into the final pattern (assembling was as big a challenge as making the tiny petal).

 

As for certain resin sets not fitting, there are cases as mentioned above where a seat might not fit because it is accurate but the kit is not. Then there are sets that don't fit the kit they are designed for.

Sets designed for a specific kit can be challenging because resin shrinks during curing (and molds can 'change' over time). Not only does resin shrink, but the shrinkage can be unpredictable and influenced by many different factors.

Bottom line is that the pattern maker needs to be experienced with the different factors and take them all into account when making a pattern. This often means making the pattern x amount oversized to compensate for shrinkage, but many/most aftermarket is made by just detailing the original kit parts and thus end up not fitting once replicated in resin.

3D printing is a great tool but resin cast copies can suffer from the same problems mentioned above.

 

:cheers:

Link to post
Share on other sites

Let me preface this by saying I have no background in engineering, and I'm a "math moron" but I know there are some really talented modelers and software engineers out there.  I think the 3D printing technology will really be a great way to create parts, projects, and improvements and over the next 5-10 years will make some major advancements and could really revolutionize our hobby.    But that's just my thoughts.

Link to post
Share on other sites
39 minutes ago, dsahling said:

think the 3D printing technology will really be a great way to create parts, projects, and improvements and over the next 5-10 years will make some major advancements and could really revolutionize our hobby.

Amen brother!

But, to be sure, there is a difference between a 3D-printed part and something made of, say, rods and sheet. I know some of the resin masters of my 1/350 YMS were 3D-printed because I could see the layers, even though there were quite fine. To be sure, the details were stunning, and I do wonder how they might have been done without 3D printing.

 

I recently purchased my first 3D kit, a 1/35 twin 40mm Bofors Naval mount. The details and complexity are amazing:

bofors_start2.jpg

 

But, they will need some clean-up:

bofors_start0.jpg

 

Link to post
Share on other sites
10 hours ago, Zactoman said:

 

Bottom line is that the pattern maker needs to be experienced with the different factors and take them all into account when making a pattern. This often means making the pattern x amount oversized to compensate for shrinkage, but many/most aftermarket is made by just detailing the original kit parts and thus end up not fitting once replicated in resin.

 

 

Exactly!

 

Have to say that it is not easy but with practice it is possible to be fairly accurate. It will never be 100% because of many variables many of which difficult to calculate but with adjustment the resin parts can be very close to a true scale replica.

 

Getting very far from our hobby in the early 90’s the task was to make masters of 43rd scale cars. The design was made on my early Mac comp and shrinkage of the eventual resin was calculated and the scale drawings modified according to them. Of course it did not work instantly, several trials had to be made but it was worth it. Casting, measuring, casting measuring and doing new main parts was the hard part of the work but the eventual result was worth it. The comp multiple view designs were “distorted” to produce a master drawing based on which with shrinkage and all the eventual resin parts turned out to be a true scale copy.

The end result were some nice cars for the manufacturer and if you take into account that even BMW chose some of them for their own shop as exclusive products then it says something about the authenticity. It was worth working on them!

 

It is unfortunate that many decades later one finds aftermarket products (CAD designed) where shrinkage is completely ignored. It was fascinating to see Eduards RS-2US missiles in 48th scale which have nothing in common with the real one. The problem is that not even the plastic RS-2US in the 48th scale MiG-21 kit are of any good. The plastic ones are too big, the resins are too small while the real scale missile is somewhere the mid-way between them. Just try and put them side by side.

 

OK, I know the manufacturer will say it is “a minor” fault and most modellers will comment “it is good for me as it is” or “looks like the real one”.

 

Best regards

Gabor

Link to post
Share on other sites

The simple answer to the OP is, using whatever skills or materials the pattern maker is comfortable with.  Styrene stock; machined metal or urethane; custom etching; milliput and foil...  Or digitally (be that through CAD or digital sculpture).

 

Hyperscale posted photos of some Black Box masters back in the day, and you can see that those are built from a mix of styrene stock for most of the shapes, with the occasional brass or PE element for smaller details, and rolls of milliput for wires and cloth.  And that where possible, only a single element is scratchbuilt, then duplicated in resin when it has to be repeated on the master.

http://acc.kitreview.com/fa18c32previewbg_1.htm

http://acc.kitreview.com/blackboxpreviewbg_3.htm

http://acc.kitreview.com/fa14cockpit32previewbg_1.htm

http://acc.kitreview.com/blackboxpreviewbg_5.htm

http://acc.kitreview.com/fa18c32previewbg_1.htm

 

Fit is down to the patternmaker's skill, technique, knowledge of materials... and just how much they care.  Some will decide a part is 'good enough', while others strive for perfection.  And that's in addition to the personal philosophy of accuracy vs. fit, discussed above.  

 

-----

 

As for 3D printing...  It is a field, not a single technology.  The best analogy I can think of is regular, 2D printing.  There is a world of difference between an old dot matrix printer, a laser printer in a home office, a colour inkjet for the home,  a commercial photo lab's inkjet and an ALPS, a full-on offset press or even the thermal printer that prints your receipts.  If you want to print some decals, you're not going to use a dot matrix printer.  If you want to publish your magazine, you're not buying a reciept printer.  If you want to print family photos, you don't want a $200 inkjet.  And if you want to print an article you found on-line, you're not firing up the offset press.

 

Same with 3D printing.

 

There are several different technologies - they make stuff in wildly different ways - from gluing and cutting individual sheets of paper together, to extruding molten plastic, to curing liquid resins with precisely controlled light, to fusing powdered materials together with laser beams, to depositing resin like an inkjet, to gluing powdered material with (essentially) super glue.  Some are faster, some are slower, some can print big stuff, some can only do small things, some are super precise, some are less accurate, some are strong, some are delicate, some are rough, some are smooth.

 

And then on top of that, you've got high-end industrial machines vs. consumer-level printers.  And (like buying a car) different capabilities as you move up each product line.

 

So for instance, here is exactly the same model printed on two different *kinds* of printer.  The one on the left looks *way* better, but the printer itself costs 5 - 10x more than the one on the right, and the material for the actual print would have a similar difference.  

 

Using the same printer, but reducing the thickness of each layer, you get this.  The one on the left is pretty good, but might need a primer coat and a light sanding; the one on the right is basically injection-molded quality straight off the printer.

 

These two are both from 'professional' printers (five figure price tags), but they're geared towards different markets - the one on the left is meant for small, detailed parts with minimal post-processing; the one on the right is meant for larger, industrial prototyping.  Again though, big difference.

 

And even with two printers that use the same fundamental technology, there can be big differences.  This is a ring, printed on a $4500 "enthusiast" printerThis is from a $15,000 professional printer.

 

Patterns printed on a really good (for modelling purposes) 3D printer will need almost no clean-up.  But, they're also really expensive, so it's not as economical to print one-offs for personal use that way.  

Edited by MoFo
Link to post
Share on other sites
On 3/11/2017 at 3:45 AM, ya-gabor said:

Exactly!

 

Something else to consider is that CAD designed parts that hang from a model aren't nearly as difficult to create as parts that fit inside or on the surface of an existing kit.

If you want to create a CAD model of a cockpit that fits inside a tapered, curved fuselage you need to make accurate measurements of that fuselage. Difficult.

If you want to make parts that fit the surface of a kit, say a new spine for a MiG-29 or conformal fuel tanks for an F-16, you need to accurately measure (and  CAD model) those complex surfaces or the parts won't fit. Very difficult.

Laser scanning the original kit parts works but it adds a whole new layer of cost and complexity.

 

 

On 3/11/2017 at 11:24 AM, MoFo said:

 

Nice write-up :thumbsup:, but please check these links.

 

:cheers:

Link to post
Share on other sites
On 3/10/2017 at 3:54 AM, ya-gabor said:

Fit of parts or no fit:

 

When designing my ejection seats, it was easy: I went out to my collection, took measurements of the real seat and made the master from it. It was fascinating to see that some kit manufacturers made cockpits where the resin seat either would not fit into or have tons of space around it. Fortunately for most the fit was good.

 

As a manufacturer it is not possible to make seats custom “distorted” to particular kit manufacturers cockpits. To make such a range would be uneconomic. I believe in making a real scale copy of the true ejection seat. There are other manufacturers with different thinking. Be it.

 

Note that if the ejection seat is the scale width, then the consoles must usually be narrower than scale because of the thickness of the side of the kit fuselage. There may also be a problem in height if the cockpit is over a nose landing-gear well of the correct depth. Also see http://tailspintopics.blogspot.com/2012/09/fitting-in.html

 

Kit manufacturers deal with the problem in different ways. I'm told that the Kitty Hawk 1/48th F2H-2 cockpit is proportionally accurate but subscale, about 1/57th.

Edited by Tailspin Turtle
Add cockpit scale
Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...